Ola`s WR450F 03` rebuild thread

I`m doing a rebuild on my WR now, so i thought i could make a thread about it, since there are few of them..

This is my first motorcycle rebuild, so i have alot of questions on my way i guess hehe..

The reason for this rebuild, is that i have a bad small end rod bearing.. So i want to change the rod, or perhaps a new crank, before it blows up on me!

Top end is in perfect shape, and i have a new piston in it already..

I have taken out the motor of the bike, and started to pull it apart.. Going to split it as soon as i have time to go in the garage again now..

But i have some questions about parts:

-What upgrade`s should i do now..?

I`m thinking of the 04 crank, if the 03 is still not upgraded and if the 04 actually fits.. I`m also going to mount the flywheel with locktite due to the woodroof key issue..

Any other good tips?

-Where to buy the parts?

Hoping to buy parts in USA, since prices are much lower there than here in norway.. Any good shops that sell parts international? TT shop perhaps?

Need crank, bearings and gaskets, primary..

I appreciate all the help i can get!


I went through this same decision when I rebuilt my '03. Yes the '04 crank will fit but you will also need to replace the flywheel and starter gear as they are different for the '04 crank. There is nothing wrong with the '03 crank as long as you have upgraded to the '04 drive parts (torque limiter) which you should do anyway even if you use the '04 crank. IMO you do not need or want to loctite the flywheel on. From what I have seen it causes more harm than good.

Pics then!

Split the motor today, and found everything in good shape, except the small end of the rod..

Wondering about one thing though.. The RIGHT (clutch side) side housing, is marked "5TA00 Y-1" and the left is "5TJ 00 Y-1".. This is correct for a 2003 WR450F? Just want to make sure that i get correct parts, since nobody knows what the last owner might have been doing...

Picture time :thumbsup:

Motor out of the bike


Clutch side housing


Split case pics




The crank


And last, the problem.. The rod small end bearing.. You can see it has wear in the middle..


Now i`m going to order 04 torq limiter,bearings, gaskets and crank, so i`m very happy for all the help i can get on where to buy them! TT shop seems to only have 03 YZ 450 parts, and no WR ? Or perhaps i can buy the YZ parts???



Piston + rings

Timing Chain


Connection rod + bearing + pin


Are same than in YZ

Crank is different because YZ doesn't have same kind of magneto than WR

Timo Mc

Ordered everything i need from http://www.yamahaaccy.com/parts.aspx today..

All bearings, gaskets, bearing torx bolts, a complete crank, and some other small stuff, for 590$ plus 58$ shipping to norway..

Alot cheaper than in norway i must say.. Just the crank costs more here..

So now it`s all about waiting, and waiting, and waiting...

Oh, by the way.. I put in a new piston this winter, after my oil drain left me.. And i have been driving for about 4-5 hours after this, mostly gentle, but a little hard after a while..

But the spark plug shows lean conditions.. On a 170MJ.. (jetted for cold winter) It was milk choclate brown before changing the piston, and now its even hotter weather that before... Any good explanations?

Is it because of the heat from the rings seating in?

Ordered everything i need from http://www.yamahaaccy.com/parts.aspx today..

All bearings, gaskets, bearing torx bolts, a complete crank, and some other small stuff, for 590$ plus 58$ shipping to norway..

And back to the start.. They NOW wanted 225$ for shipping all of a sudden, so i guess i have to find someone else that uses normal airmail rates..

And the sun is shining...

Good luck on the rebuild and please keep us posted on how you get on.

I have ordered all the parts from http://www.yamahaaccy.com/parts.aspx after all, and they are supposed to get here any day now..

One thing i`m not sure of:

How do i loosen the torx bolts on each bearing? Heat up alot, then use force when opening them? I recon they sit tight, since they are locked with some kind of tool, that made a dent in them, keeping them from loosening..

You can see the bolts here, the 2 by the main bearing for example:


They are peened closed. Get kelstr or grayracers opinion.

just sendt kelstr a PM..

perhaps pbdblue here also knows? Since he also had rebuildt his bike..?

They are loctited with red loctite and punched from the factory. I got all of them out except for one using a torx bit and an impact driver. One I had to drill out. Some heat may help break the loctite loose. My cases were broken so I didn't need to worry about that but I needed the bearing retainers. When you reassemble use red loctite and punch the screw head into the relief on the retainer.


Kelstr also mentioned the hammer impact tool in his answer, so i guess i will try to borrow me one of those...


Got my parts today!

No problems on openin those bolts..

BUT.. How do i get out the bearings on the transmission? Like, the one on the left side, just behind where the clutch arm goes down.. Do i need a special tool there? I can not push it out from behind, thats for sure..

Heat area around bearing with the blow torch and hit your work table with the case.

They will pop out.

Use a rag, to soften the direct impact, and try hitting with the case whole gasket area at once, to spread the hit.

If heating doesnt work, heat it more.

Eventually itll let go.

Ive recently done this to an mx er, one bearing struggeled abnormally, but eventually it came out after 4 times heating and bashing.

Case sustained no damage to the gasket area.

Hit strong, with precision and with a great deal of feelling.

To remove the bearings - put the cases in a oven at 150 deg C for about 20 minutes. The bearings should fall out by them selves (or with light tapping). I used the same process to put the bearings in.

Got it together today!

Started right up on 3rd kick!

Everything looks great so far, after a 5-6km test run, and no leaks! At least none big ones as i can see yet!

Only issue was that the new FMF ti powercore i mounted, touched the plastic numberplate, and melted it a little.. moved it from the pipe with a nut behind the cover, so it shouldnt do that anymore..!

How hot does those exhaust pipes/mufflers actually get with only normal driving? It gets pretty hot imo..

Ola, a happy man so far :ride:

It's amazingly satisfying to do your own work, no matter how big or small the job. Congratulations on completing a complex repair. Everybody should try to do as much of their own work as possible. Obviously some repairs are going to be more than some people can manage but you only learn by doing. Having this forum as a resource is a big help.

Satisfying indeed!!

Went out for more riding tonight.. Around half a tank of driving.. Opened it up a little now and then, and i`m very satisfyed how the engine is working now! Strong pull all the way, and it feels faster than it ever was before!

Changed out jetting before starting to 48# pilot, 70# starter and a 170# main blu JD 3rd-clip, running both hotcams, Ti powercore (alot louder than expected) and more holes in the airbox.. Fuel screw zip tye at 1 1/4.. Feels a little rich on acc..

Looking forward to let it go WOT !!

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